Japan’s leading mobile operator DoCoMo has announced plans to expand its LTE service ‘Xi’ after it won regulatory approval from the Japanese Minister for Internal Affairs and Communications to offer the service using new bandwidth.

The move will see the operator, which has more than 50 percent market share, begin preparing to use the 700 MHz band to “expand and improve” the LTE service, which was recently revealed to have accumulated 3 million users. Demand for Xi — pronounced crossy — has been brisk and DoCoMo has added 1 million new subscribers in the four months between March and June.

The changes won’t come for some time as DoCoMo says that it expects to begin offering LTE using the 700 MHz band in January 2015, but by then a far larger percentage of Japan’s mobile phone owners are likely to be using the service, and LTE services from its rivals, making expansion plans imperitive.

The move to use another band comes as the operator, and others in Japan, worry about recent increases in data traffic across their networks. Mobile messaging services — like Japan-headquartered Line and Korea’s Kakao Talk — offer free calling and ‘always-on’ services that consume significant amounts of data.

The issue flared up after an unnamed mobile VoIP was cited by the operator as the cause network outage issues for a day during January.

DoCoMo’s LTE network was among the first to launch worldwide, but it is not yet available for Apple’s new iPad as the operator has not agreed a partnership with the Cupertino-based company.

Such a tie-up looks increasingly unlikely, as DoCoMo is focused on Android and called any move towards the iPhone and iPad “difficult” due to Apple’s shipment demands. There is also the issues that DoCoMo will not be able to pre-bundle its proprietary software and services on the devices.